/****************************************************************************
 * libc/time/lib_strftime.c
 *
 *   Copyright (C) 2009, 2011, 2013 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/


#include "los_typedef.h"
#include "stdio.h"

#if defined(__LP64__)
#define mktime64 mktime
#include "time.h"
#else
#include "time64.h"
#endif


/****************************************************************************
 * Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Type Declarations
 ****************************************************************************/

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Public Constant Data
 ****************************************************************************/

/****************************************************************************
 * Public Data
 ****************************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

static const char * const g_abbrevmonthname[12] =
{
  "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};

static const char * const g_monthname[12] =
{
  "January", "February", "March",     "April",   "May",      "June",
  "July",    "August",   "September", "October", "November", "December"
};

static const char *const g_abbrevWeekdayname[7] =
{
  "Sun","Mon","Tue","Wed","Thu","Fri","Sat",
};

static const char *const g_Weekdayname[7] =
{
  "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday","Friday", "Saturday"
};


/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Function:  strftime
 *
 * Description:
 *   The  strftime()  function  formats the broken-down time tm according to
 *   the format specification format and places the result in the  character
 *   array s of size max.
 *
 *   Ordinary characters placed in the format string are copied to s without
 *   conversion.  Conversion specifications are introduced by a '%'  charac-
 *   ter,  and  terminated  by  a  conversion  specifier  character, and are
 *   replaced in s as follows:
 *
 *   %b     The abbreviated month name according to the current locale.
 *   %B     The full month name according to the current locale.
 *   %C     The century number (year/100) as a 2-digit integer. (SU)
 *   %c     The preferred date and time representation for the current locale.
 *   %d     The day of the month as a decimal number (range 01 to 31).
 *   %e     Like %d, the day of the month as a decimal number, but a leading
 *          zero is replaced by a space.
 *   %h     Equivalent to %b.  (SU)
 *   %H     The hour as a decimal number using a 24-hour clock (range 00 to 23).
 *   %I     The  hour as a decimal number using a 12-hour clock (range 01 to 12).
 *   %j     The day of the year as a decimal number (range 001 to 366).
 *   %k     The hour (24-hour clock) as a decimal number (range  0  to  23);
 *          single digits are preceded by a blank.  (See also %H.)  (TZ)
 *   %l     The  hour  (12-hour  clock) as a decimal number (range 1 to 12);
 *          single digits are preceded by a blank.  (See also %I.)  (TZ)
 *   %m     The month as a decimal number (range 01 to 12).
 *   %M     The minute as a decimal number (range 00 to 59).
 *   %n     A newline character. (SU)
 *   %p     Either "AM" or "PM" according to the given time  value, or the
 *          corresponding  strings  for the current locale.  Noon is treated
 *          as "PM" and midnight as "AM".
 *   %P     Like %p but in lowercase: "am" or "pm" or a corresponding string
 *          for the current locale. (GNU)
 *   %s     The number of seconds since the Epoch, that is, since 1970-01-01
 *          00:00:00 UTC. (TZ)
 *   %S     The second as a decimal number (range 00 to 60).  (The range is
 *          up to 60 to allow for occasional leap seconds.)
 *   %t     A tab character. (SU)
 *   %y     The year as a decimal number without a century (range 00 to 99).
 *   %Y     The year as a decimal number including the century.
 *   %%     A literal '%' character.
 *
 * Returned Value:
 *   The strftime() function returns the number of characters placed in  the
 *   array s, not including the terminating null byte, provided the string,
 *   including the terminating null byte, fits.  Otherwise,  it returns 0,
 *   and the contents of the array is undefined.
 *
 ****************************************************************************/

size_t strftime(char *s, size_t max, const char *format,
                const struct tm *tm)
{ /*lint !e578*/
    const char *str;
    char       *dest   = s;
    int             chleft = max;
    int             len = 0;
    char *buf;

    while (*format && chleft > 0)
    {
    /* Just copy regular characters */

        if (*format != '%')
        {
            *dest++ = *format++;
            chleft--;
            continue;
        }

    /* Handle the format character */

        format++;
        len   = 0;

        switch (*format++)
        {
            /* %a: A three-letter abbreviation for the day of the week. */
            /* %A: The full name for the day of the week. */

            case 'a':
            {
                if (tm->tm_wday < 7)
                {
                    str = g_abbrevWeekdayname[tm->tm_wday];
                    len = snprintf(dest, chleft, "%s", str);
                }
            }
            break;
            case 'A':
            {
                if (tm->tm_wday < 7)
                {
                    str = g_Weekdayname[tm->tm_wday];
                    len = snprintf(dest, chleft, "%s", str);
                }
            }
            break;

            /* %h: Equivalent to %b */

            case 'h':

            /* %b: The abbreviated month name according to the current locale. */

            case 'b':
            {
                if (tm->tm_mon < 12)
                {
                    str = g_abbrevmonthname[tm->tm_mon];
                    len = snprintf(dest, chleft, "%s", str);
                }
            }
            break;

            /* %B: The full month name according to the current locale. */

            case 'B':
            {
                if (tm->tm_mon < 12)
                {
                    str = g_monthname[tm->tm_mon];
                    len = snprintf(dest, chleft, "%s", str);
                }
            }
            break;

            /* %y: The year as a decimal number without a century (range 00 to 99). */

            case 'y':
            {
                len = snprintf(dest, chleft, "%02d", tm->tm_year % 100);
            }
            break;

            /* %C: The century number (year/100) as a 2-digit integer. */

            case 'C':
            {
                len = snprintf(dest, chleft, "%02d", (tm->tm_year + 1900) / 100);
            }
            break;

            /* %c: The preferred date and time representation for the current locale. */

            case 'c':
            {
                buf = asctime(tm);
                if (buf)
                {
                    len = snprintf(dest, chleft, "%s", buf);
                }
            }
            break;

            /* %d: The day of the month as a decimal number (range 01 to 31). */

            case 'd':
            {
                len = snprintf(dest, chleft, "%02d", tm->tm_mday);
            }
            break;

            /* %e: Like %d, the day of the month as a decimal number, but a leading
            * zero is replaced by a space.
            */

            case 'e':
            {
                len = snprintf(dest, chleft, "%2d", tm->tm_mday);
            }
            break;

            /* %H: The hour as a decimal number using a 24-hour clock (range 00  to 23). */

            case 'H':
            {
                len = snprintf(dest, chleft, "%02d", tm->tm_hour);
            }
            break;

            /* %I: The  hour as a decimal number using a 12-hour clock (range 01 to 12). */

            case 'I':
            {
                len = snprintf(dest, chleft, "%02d", (tm->tm_hour % 12 == 0) ? 12 : (tm->tm_hour % 12));
            }
            break;

            /* %j: The day of the year as a decimal number (range 001 to 366). */

            case 'j':
            {
                if (tm->tm_mon < 12)
                {
                    len   = snprintf(dest, chleft, "%03d", tm->tm_yday + 1);
                }
            }
            break;

            /* %k: The hour (24-hour clock) as a decimal number (range  0  to  23);
            * single digits are preceded by a blank.
            */

            case 'k':
            {
                len = snprintf(dest, chleft, "%2d", tm->tm_hour);
            }
            break;

            /* %l: The  hour  (12-hour  clock) as a decimal number (range 1 to 12);
            * single digits are preceded by a blank.
            */

            case 'l':
            {
                len = snprintf(dest, chleft, "%2d", (tm->tm_hour % 12 == 0) ? 12 : (tm->tm_hour % 12));
            }
            break;

            /* %m: The month as a decimal number (range 01 to 12). */

            case 'm':
            {
                len = snprintf(dest, chleft, "%02d", tm->tm_mon + 1);
            }
            break;

            /* %M: The minute as a decimal number (range 00 to 59). */

            case 'M':
            {
                len = snprintf(dest, chleft, "%02d", tm->tm_min);
            }
            break;

            /* %n: A newline character. */

            case 'n':
            {
                *dest = '\n';
                len   = 1;
            }
            break;

            /* %p: Either "AM" or "PM" according to the given time  value. */

            case 'p':
            {
                if (tm->tm_hour >= 12)
                {
                    str = "PM";
                }
                else
                {
                    str = "AM";
                }
                len = snprintf(dest, chleft, "%s", str);
            }
            break;

            /* %P: Like %p but in lowercase: "am" or "pm" */

            case 'P':
            {
                if (tm->tm_hour >= 12)
                {
                    str = "pm";
                }
                else
                {
                    str = "am";
                }
                len = snprintf(dest, chleft, "%s", str);
            }
            break;

            /* %s: The number of seconds since the Epoch, that is, since 1970-01-01
            * 00:00:00 UTC.  Hmmm... mktime argume is not 'const'.
            */

            case 's':
            {
                len = snprintf(dest, chleft, "%lld", mktime64((struct tm *)tm));
            }
            break;

            /* %S: The second as a decimal number (range 00 to 60).  (The range  is
            * up to 60 to allow for occasional leap seconds.)
            */

            case 'S':
            {
                len = snprintf(dest, chleft, "%02d", tm->tm_sec);
            }
            break;

            /* %t: A tab character. */

            case 't':
            {
                *dest = '\t';
                len   = 1;
            }
            break;

            /* %Y: The year as a decimal number including the century. */

            case 'Y':
            {
                len = snprintf(dest, chleft, "%04d", tm->tm_year + 1900);
            }
            break;

    /* %%:  A literal '%' character. */

            case '%':
            {
                *dest = '%';
                len   = 1;
            }
            break;
        }

    /* Update counts and pointers */

        dest   += len;
        chleft -= len;
    }

    /* We get here because either we have reached the end of the format string
    * or because there is no more space in the user-provided buffer and the
    * resulting string has been truncated.
    *
    * Is there space remaining in the user-provided buffer for the NUL
    * terminator?
    */

    if (chleft > 0)
    {
        /* Yes, append terminating NUL byte */

        *dest = '\0';

        /* And return the number of bytes in the resulting string (excluding
        * the NUL terminator).
        */

        return max - chleft;
    }

    /* The string was truncated and/or not properly terminated.  Return
    * zero.
    */

    return 0;
}
